problem installing a domU

["Steven M. Bellovin" <smb%cs.columbia.edu@localhost>]

I've create a new amd64/netbsd5-HEAD dom0; I'm now trying to go through
the official installation process to create a domU.  When I try to boot
an installation kernel, though, I get this:

NetBSD 5.0_STABLE (INSTALL_XEN3_DOMU) #2: Mon Aug 10 03:59:45 EDT 2009
        
root%hemu.machshav.com@localhost:/usr/msrc/BUILD/obj/sys/arch/amd64/compile/INSTALL_XEN3_DOMU
total memory = 128 MB
avail memory = 111 MB
mainbus0 (root)
hypervisor0 at mainbus0: Xen version 3.3
vcpu0 at hypervisor0: AMD 686-class, 2410MHz, id 0x50ff2
xenbus0 at hypervisor0: Xen Virtual Bus Interface
xencons0 at hypervisor0: Xen Virtual Console Driver
xencons0: using event channel 2
xbd0 at xenbus0 id 773: Xen Virtual Block Device Interface
xennet0 at xenbus0 id 0: Xen Virtual Network Interface
xennet0: MAC address 00:16:3e:42:e0:f3
xennet1 at xenbus0 id 1: Xen Virtual Network Interface
xennet1: MAC address 00:16:3e:6b:27:aa
raidattach: Asked for 8 units
Kernelized RAIDframe activated
Searching for RAID components...
boot device: xbd0
root on md0a dumps on md0b
mountroot: trying lfs...
mountroot: trying ffs...
mountroot: trying ext2fs...
mountroot: trying nfs...
mountroot: trying smbfs...
mountroot: trying ntfs...
mountroot: trying msdos...
mountroot: trying cd9660...
mountroot: trying coda...
no file system for md0 (dev 0x1100)
cannot mount root, error = 79

On a normal system, that error generally means I've forgotten to
populate /stand with modules.  I have no idea what it might mean here.
It's clearly an installation kernel (albeit home-compiled), since it
knows that root is md0a.  Suggestions?  Here are the non-comment lines
of the config file:

kernel = "/usr/pkg/etc/xen/INSTALL-netbsd5"

memory = 128

name = "handcar"

vif = [ 'mac=00:16:3e:42:e0:f3, bridge=bridge0', 'bridge=bridge1' ]

disk = [ 'file:/usr/vnd/handcar.vnd,0x301,w',
 'file:/usr/vnd/pkgsrc.vnd,0x302,r', 'file:/usr/vnd/src.vnd,0x303,r' ,
 'file:/usr/vnd/torrent.vnd,0x304,r' ]
disk = [ 'file:/usr/vnd/amd64cd.iso,0x305,r' ]

root = "xbd0a"


on_poweroff = 'destroy'
on_reboot   = 'restart'
on_crash    = 'restart'



                --Steve Bellovin, http://www.cs.columbia.edu/~smb